Table 1 Clinical characters before and after matching

Gender

 Male

157 (66.8%)

66

91

0.821

66

61

0.463

 Female

78 (33.2%)

34

44

34

39

Age

65 (range: 37–85)

 ≥ 60

160 (68.1%)

66

94

0.555

66

74

0.217

 < 60

75 (31.9%)

34

41

34

26

Smoking history

 Yes

93 (39.6%)

36

57

0.335

36

41

0.467

 No

142 (60.4%)

64

78

64

59

Tumor location

 Cervical

2 (0.8%)

1

1

0.093

1

1

0.729

 Upper thoracic

26 (11.1%)

15

11

15

10

 Middle thoracic

102 (43.3%)

44

58

44

44

 Lower thoracic

105 (44.7%)

40

65

40

55

Stage

 T

  1

35 (14.9%)

11

24

0.207

11

14

0.239

  2

51 (21.7%)

18

33

18

27

  3

115 (48.9%)

54

61

54

49

  4

34 (14.5%)

17

17

17

10

 N

  0

61 (26.0%)

22

39

0.234

22

23

0.866

  1–3

174 (74.0%)

78

96

78

77

 M

  0

165 (70.2%)

75

90

0.167

70

64

0.112

  1

70 (29.8%)

25

45

25

36

 TNM stage

  I

27 (11.5%)

6

21

0.039

6

13

0.342

  II

38 (16.2%)

16

22

16

14

  III

60 (25.5%)

32

28

32

26

  IV

110 (46.8%)

46

64

46

47

Surgery

 Yes

95 (40.9%)

28

67

0.001

28

40

0.073

 No

140 (59.1%)

72

68

72

60